1. Field of the Invention
This invention relates to an improved conductor assembly comprising uniquely formed lead frame conductors used to attach a semiconductor chip to a socket or pc board. Each lead frame conductor of the invention has one end coined to form a land or wire bonding area and each is arranged to extend over and be joined to the surface of a chip.
2. Description of the Prior Art
U.S. Pat. No. 4,862,245 assigned to the same assignee as the present invention describes a technique for positioning and fixing leads to a semiconductor chip prior to encapsulation of the chip in a protective coating by extending the lead frame over the surface of the chip.
During the forming operation for creating the lead frames used with such encapsulated devices the surface of the lead frame fingers become crowned, i.e. the covers become quite rounded, and hemispherical. It has been found that it is difficult to bond wires to these crowned surfaces. Thus, during the operation where wires are being bonded between the pads on the chip and the lead frame as taught in U.S. Pat. No. 4,862,245, defects can occur.
It is an object of this invention to provide an improved lead frame conductor with an improved land or wire bonding area thereon.
It is a further object to create an improved lead frame conductor that can be fully joined to an insulative layer.
A further object of the invention is to provide a plastic encapsulated semiconductor package which when connected with lead frame members provided with improved lands or wire bonding areas has enhanced electrical and thermal coupling between the underlying semiconductor chip and the lead frame as well as improved mechanical interlocking of the lead frame to the encapsulant.
These and other objects of the present invention are provided by a lead frame provided with improved lands for contacts to a semiconductor chip. The lead frame comprises a plurality of figured conductors in which the proximal end of each conductor is arranged in a desired pattern having fixed spacing and is provided with a land region suitable for bonding wires extending from a semiconductor chip thereto. The distal ends of the conductors fan out into a selected configuration and are adapted to connect with electrical voltage and external signal and voltage lines.
These and other objects, features and advantages of the invention will become more apparent from the following particular description of the preferred embodiment of the invention as illustrated in the accompanying drawings.